Fig. 3. Methane fluxes during incubation of surface crust material from storages with untreated cattle slurry (UCS) or anaerobically digested cattle slurry (DCS). The subscript terms C and 0 indicate presence or absence, respectively, of an additional solid cover. After an initial rate determination, the material was partially dried, and later rewetted, both times with determination of CH₄ fluxes (see text). The data represent mean ± standard error (n = 3). OM, organic matter.